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Summary of Business and Significant Accounting Policies (Product Warranty Expense) (Details) - USD ($)
12 Months Ended
Jan. 31, 2020
Jan. 31, 2019
Jan. 31, 2018
Warranty [Line Items]      
Accrued warranty balance $ 800,000 $ 700,000 $ 925,000
Product Warranty Accrual, Current $ 325,000 $ 325,000  
Minimum [Member]      
Warranty [Line Items]      
Product warranty period 10 years    
Maximum [Member]      
Warranty [Line Items]      
Product warranty period 10 years